God must have certain characteristic qualities (such as providing purpose to life), otherwise he would not be God.

But it is impossible for any entity to possess some of these qualities (such as providing purpose to life since we can find no real purpose and therefore we in practice have no ultimate purpose to our lives) that are essential to God.

Therefore since some of God’s essential qualities (such as being the purpose provider to life) cannot possibly exist in any entity, God cannot exist.

This argument is so weak, that it has to have an example built into it in order to seem valid. In order to emphasize this problem, here is the argument again by itself, without the flimsy, parenthetical support.

God must have certain characteristic qualities, otherwise he would not be God.

But it is impossible for any entity to possess some of these qualities that are essential to God.

Therefore since some of God’s essential qualities cannot possibly exist in any entity, God cannot exist.

The reason the parenthetical example about the purpose of life is weak is because we do not need to understand the purpose of life in order for there to be a purpose.

For example, if a child was taking a test in kindergarten, that child would not need to understand the principles of early childhood development, elementary school administration, or teacher accountability in order for that test to have a purpose. The test has a purpose regardless of whether or not the child is aware of it.

In addition, the claim that we "can find no real purpose" is unsupported. Theists claim that we can certainly find purpose through such sources as "religious experience", or sacred texts. The validity of these sources is still debated between theists and atheists, so the argument is just begging the question by assuming these sources are invalid.

So this argument cannot even be considered valid until some consensus is made regarding the validity of spiritual sources. But that would end the debate of whether or not God exists.Therefore, this argument simply cannot ever be considered a valid argument. If we were ever in a position where it could, then the question will have already been answered.

But even without the poor example, this argument is still just a recycled version of other arguments, such as the Problem of Evil and the Aggregate of Qualities Argument. Not only does this argument bring absolutely nothing new to the debate over God's existence, but even if it did, it would be no stronger, but much less supported, than arguments that have already been around for a long time.